JP6887385B2 - Catalytic filter with end coating for lean engine exhaust - Google Patents

Description

The present invention generally relates to catalyst articles, emission treatment systems and exhaust gas treatment methods. The present invention specifically relates to such articles, systems, and methods for treating diesel engine exhaust.

Background Technology Engine exhaust, especially diesel engine exhaust, is a mixture of dissimilar components, which is a gaseous emissions, such as carbon monoxide (“CO”), unburned hydrocarbons (“HC”). , And nitrogen oxides (“NO _x ”), as well as condensed phase substances (liquids and solids), commonly referred to as particulate or particulate matter. Controlled species of exhaust emissions include carbon monoxide (CO), nitrogen oxides (NO _x ), hydrocarbons (HC) and particulate matter (PM).

Diesel engine exhaust systems are often provided with a catalyst composition and a substrate on which the catalyst composition is placed in order to convert a certain amount or all of these exhaust components into harmless components. For example, a diesel exhaust system can have one or more diesel oxidation catalysts, a soot filter, and a catalyst for reducing _{NO x.}

Oxidation catalysts containing platinum group metals, base metals and combinations thereof are known to facilitate the treatment of diesel engine exhausts, which allow both the gaseous pollutants HC and CO, and particulate matter. Conversion of some proportion of the state material is promoted and oxidizes these pollutants to carbon dioxide and water. Such a catalyst is commonly contained in a unit called a diesel oxidation catalyst (DOC), which is placed in the exhaust of a diesel engine to treat the exhaust and then release it into the atmosphere. In addition to the conversion of gaseous HC, CO and particulate matter, oxidation catalysts containing platinum group metals, which are usually located on flame-retardant oxide carriers, are also nitrogen oxides (NO). Promotes oxidation to NO _2.

The exhaust gas of diesel exhaust particulate matter (TPM) is mainly composed of three components. One component is a dry solid carbon fraction, or soot fraction. This dry carbon material provides visible soot emissions commonly associated with diesel exhaust. The second component of the particulate matter is the soluble organic fraction (“SOF”). Soluble organic compounds are sometimes referred to as volatile organic compounds (“VOFs”), and the term will be used here as well. The VOF can exist in the diesel exhaust as vapor or as an aerosol (fine droplets of liquid condensate), depending on the temperature of the diesel exhaust. It generally exists as a condensed liquid in diluted exhaust at a standard particle collection temperature of 52 ° C. (as described in standard measurement tests, such as the US Heavy Duty Transient Federal Test Procedure). These liquids come from two sources: (1) lubricating oil that is wiped from the cylinder wall of the engine each time the piston moves up and down, and (2) diesel fuel that is not or partially burned. The third component of the particulate matter is the so-called sulfate fraction. The sulfate fraction is formed from a small amount of sulfur components present in diesel fuel and lubricating oil. During combustion, the sulfur components of diesel fuel and oil form gaseous SO ₂ and SO ₃ . When the exhaust is cooled, SO ₃ quickly combines with water to form sulfuric acid (H ₂ SO ₄ ). Sulfuric acid, along with the carbon particles, forms an aerosol that is collected as a condensed phase or is adsorbed on other particulate components, thereby adding to the mass of the TPM.

A key post-treatment technique in applications for the high reduction of particulate matter is the diesel particulate filter (DPF). There are many known filter structures that are effective in removing particulate matter from diesel exhaust, such as honeycomb wall flow filters, roll-up or filled fiber filters, continuous pore foams, sintered metal filters, etc. is there. However, the ceramic wall flow filters described below have received the most attention. This filter can remove more than 90% of solid carbon particulate matter from diesel exhaust. This filter is a physical structure for removing particles from the exhaust, and the accumulated particles will increase the back pressure from the filter in the engine. For this reason, the accumulated particles must be burned out of the filter continuously or periodically to maintain an acceptable back pressure. Unfortunately, carbon soot particles require a temperature above 500 ° C. to burn under oxygen-rich (lean) exhaust conditions. This temperature is higher than the temperature normally present in diesel exhaust.

Therefore, in general, efforts are being made to raise the exhaust temperature in order to actively regenerate the filter. The presence of the catalyst associated with the filter helps CO, HC and NO oxidation in the filter and improves the soot burning rate. In this way, catalytic soot filters (CSF), or catalytic diesel particulate filters (CDPF), are effective in achieving> 90% reduction in particulate matter, along with active combustion of accumulated soot. ..

Another mechanism for removing particles is to _{use NO 2} as an oxidant in the exhaust stream. In this way, the fine particles can be removed by oxidation using _{NO 2} as an oxidizing agent at a temperature of more than 300 ° C. _{NO 2} already present in the exhaust from the engine can be supplemented by oxidizing NO (also in the exhaust) upstream by using a DOC oxidation catalyst. This passive regeneration mechanism can further reduce the amount of soot carried in the filter and can reduce the number of active regeneration cycles.

Emissions standards that will be adopted worldwide in the future will also state _{NO x reductions from diesel emissions. The NO x} reduction technology that has been applied and demonstrated in heavy-duty vehicle emission systems since 2006 in Europe and 2010 in the United States is selective catalytic reduction (SCR). _{In this method, NO x} is reduced with ammonia (NH ₃ ) to nitrogen (N ₂ ) on a catalyst usually composed of base metals. This technique _{can reduce NO x} by more than 90%, thus presenting one of the best approaches to achieving _{ambitious NO x reduction goals.} SCRs for automotive applications use urea (usually present in aqueous solution) as the source of ammonia. The SCR results in efficient conversion of _{NO x} as long as the exhaust temperature is within the active temperature range of the catalyst.

Separate substrates, each containing a catalyst for arranging the individual components of the exhaust, can be provided within the exhaust system, while reducing the overall size of the system and facilitating the assembly of the system. And in order to reduce the overall cost of the system, it is desirable to use fewer substrates. One approach to achieving this goal is to coat the soot filter with a catalytic composition that is effective in converting _{NO x into harmless components (“SCR Catalyzed Soot Filter”).} can get). The SCR catalytic soot filter is assumed to have two catalytic functions: removing particulate components of the exhaust stream _{and converting the NO x} component of the _{exhaust stream to N 2} .

For _{a coated soot filter capable of achieving the NO x} reduction target, it is necessary to sufficiently support the SCR catalyst composition on the soot filter. Exposure to certain harmful components of the exhaust stream gradually loses the catalytic effect of the composition over time, increasing the need for greater catalytic loading of the SCR catalytic composition. However, the manufacture of soot filters coated with higher catalyst loading can lead to unacceptably high back pressure in the exhaust system. Therefore, there is a need for a coating technique that allows for higher catalyst loading in wall flow filters and still allows filters to maintain flow characteristics that achieve acceptable back pressure.

A further aspect to consider when coating wall flow filters is to select the appropriate SCR catalyst composition. First, the catalytic composition must be durable so that the SCR catalytic activity is maintained even after prolonged exposure to the high temperatures characteristic of filter regeneration. For example, combustion of soot fractions of particulate matter often involves temperatures above 700 ° C. Such temperatures reduce the catalytic effect of many commonly used SCR catalytic compositions, such as mixed oxides of vanadium and titanium. Secondly, since the SCR catalyst composition preferably has a sufficiently wide operating temperature, such a catalyst composition can adjust the variable temperature range in which the passenger car operates. Temperatures below 300 ° C. usually occur, for example, under low loading conditions, or engine start-up. The SCR catalytic composition is preferably capable of catalyzing the reduction _{of the NO x component of the exhaust in order to achieve the NO x} reduction target and further to achieve this at lower exhaust temperatures.

Ammonia can slip through a filter coated with the SCR catalyst composition, so it is often necessary to provide a downstream catalyst to oxidize such slipped ammonia. .. The ammonia oxidation catalyst containing the platinum group metal can be placed on the outlet end of the wall flow filter as a washcoat to oxidize the ammonia. Coating on the wall flow filter is applied by vertically impregnating the wall flow substrate into the catalytic slurry of solid particles in liquid, resulting in a carried wash coat by the wall elements of the wall flow filter. Be done. Depending on various factors, the wash coat invades the wall. This means that the washcoat has penetrated at least most of the hollow areas within the wall thickness and has been deposited on the inner surface over the wall thickness. Alternatively, the washcoat may be supported on the outer surface of the wall. In either case, the capillary action of the slurry when the wall flow monolith is impregnated into the slurry makes it difficult to tightly control the length of the coating applied to the wall flow filter. This is not a problem if the entire filter should be covered with a catalytic composition. However, when two or more catalyst compositions are applied to a wall flow filter, the coating should be tightly controlled to extend from the edges of the wall flow filter to minimize negative catalyst component interactions. Can be desirable. For example, it may be desirable to provide a wall flow filter having an SCR catalyst composition extending from the inlet of the filter and an oxidation catalyst composition extending from the outlet end of the filter, where the SCR catalyst component and the oxidation catalyst component Two coatings are applied to minimize the interaction.

Catalytic articles, methods and systems that treat carbon monoxide, nitrogen oxides, hydrocarbons and particulate matter from diesel engines in an effective and inexpensive manner while minimizing the space required in the exhaust system. There is a need for this in the art. There is also a need to provide catalytic articles, methods and systems that minimize negative interactions between different coating compositions.

Outline of the Invention Various embodiments are listed below. It will be appreciated that the embodiments listed below can be combined not only as listed below, but also in other suitable combinations according to the scope of the invention.

Embodiments of the present invention, by using a single catalyst article main emissions in the exhaust (i.e., CO, HC, NO _x, soot, NH _3, and H ₂ S) to reduce one or more Regarding a catalytic particulate filter for controlling diesel exhaust emissions. In some embodiments, the present disclosure describes a multi-zone catalytic article, a method of manufacturing the multi-zone catalytic article, and a method for controlling emissions in a lean burn (eg, diesel) engine exhaust stream with the multi-zone catalytic article. Bring. In some embodiments, a single multi-zone catalytic article can be used to provide an emission treatment system capable of effectively treating diesel engine exhaust.

The first embodiment is
Multiple porous walls extending longitudinally to form parallel passages extending from the inlet end to the exit end, where a number of passages are open at the entrance end and at the exit end. An inlet passage closed by an outlet plug, many passages are outlet passages closed by an inlet plug at the entrance end and open at the outlet end, and the outlet plug is a depth and outlet plug end face. The outlet end defines the outlet end surface of the outlet passage, including the outlet plug and the outlet plug end face.
Selective catalytic reduction (SCR) catalyst applied to the porous wall of the particulate filter, and platinum group metal (PGM) end coating, platinum group metal coating (PGM) end covering the outlet end surface and the outlet end face of the plug. Extends from the surface of the outlet end at a distance of less than 1.5 times the depth of the outlet plug and has a local carrying amount of platinum group metal (PGM) in the range of ^{about 20 to about 200 g / ft 3.} ,
The present invention relates to a catalytic particulate filter having. In the second embodiment, the catalytic particulate filter of the first embodiment is modified so that the plug at the outlet end has a length in the range of about 3 mm to about 8 mm.

In the third embodiment, the catalytic particulate filter of the first and second embodiments is an end face in which the platinum group metal end coating is applied only to the outlet end surface and the outlet end face of the plug by the applicator. It has been transformed as it is. In a fourth embodiment, the catalytic particulate filter of the third embodiment is modified such that the applicator is selected from the group consisting of brushes, rollers, squeegees and stamp pads. In the fifth embodiment, the catalytic particulate filter of the second and third embodiments is modified so that the applicator is a roller.

In the sixth embodiment, in the catalytic particulate filter of the first to fifth embodiments, the platinum group metal end coating is the same as or less than the distance from the outlet end surface to the depth of the outlet plug. It is deformed to stretch with. In the seventh embodiment, the catalytic particulate filter of the first to sixth embodiments has a platinum group metal end coating supported in the range of ^{about 20 g / ft 3} to about 150 g / ft ^3. It has been transformed into. In the eighth embodiment, the catalytic particulate filter of the first to seventh embodiments is modified so that the platinum group metal for end coating is palladium.

In the ninth embodiment, in the catalytic particulate filter of the first to eighth embodiments, the filter is further in the range of more than about 10% to about 50% of the wall length from the outlet end of the passage. It has been modified to have an oxidation catalyst washcoat containing a platinum group metal that extends over depth. In the tenth embodiment, the catalytic particulate filter of the first to ninth embodiments is modified so that the selective catalytic reduction catalyst coating extends over the entire length of the porous wall.

In the eleventh embodiment, the catalytic particulate filter of the first to tenth embodiments is modified so that the selective catalytic reduction catalyst coating penetrates the porous wall. In the twelfth embodiment, the catalytic particulate filter of the first to eleventh embodiments is modified so that the selective catalyst reduction catalyst overlaps with the oxidation catalyst wash coat. In the thirteenth embodiment, the catalytic particulate filter of the first to twelfth embodiments is modified so that the oxidation catalyst wash coat overlaps with the selective catalyst reduction catalyst.

In the fourteenth embodiment, the catalytic particulate filter of the first to thirteenth embodiments is modified such that the selective catalytic reduction catalyst has a base metal-promoted molecular sieve. In the fifteenth embodiment, in the catalytic particulate filter of the first to fourteenth embodiments, the selective catalytic reduction catalyst is Cu, Fe, Co, Ni, La, Ce, Mn, V, Ag and these. It has been modified to be a metal-promoted zeolite skeleton material selected from the combinations of. In the sixteenth embodiment, the catalytic particulate filter of the first to fifteenth embodiments has a CHA skeleton in which the selective catalytic reduction catalyst is promoted with a metal selected from Cu, Fe and a combination thereof. It has been transformed to be a zeolite. In the seventeenth embodiment, in the catalytic particulate filter of the first to sixteenth embodiments, the platinum group metal end coating is only the platinum group metal coating on the catalytic particulate filter. It has been transformed.

In the eighteenth embodiment, the lean combustion engine exhaust system has a diesel oxidation catalyst upstream from the catalytic particulate filter of any of the first to seventeenth embodiments. In the nineteenth embodiment, the lean combustion engine exhaust system has a lean NO _x trap upstream from the catalytic particulate filter of any of the first to seventeenth embodiments.

In the twentieth embodiment, the method for producing a catalytic soot filter is
The process of coating a catalytic soot filter containing multiple porous walls that extend longitudinally and form multiple parallel passages extending from the inlet end to the outlet end, where numerous passages are at the inlet end. An entrance passage that is open at the exit end and closed by an exit plug at the exit end, and a number of passages are exit passages that are closed by the entrance plug at the entrance end and open at the exit end. The plug has a depth and an outlet plug end face, the outlet end defines the outlet end surface including the outlet plug end face, where coating the catalytic soot filter is a selective catalytic reduction catalyst washcoat. A step of contacting the outlet plug end face and the outlet end surface with an applicator containing a platinum group metal coating, which comprises wash-coating on the porous wall of the catalyst filter, whereby the platinum group metal coating is applied. Move from the catalyst to the outlet plug end face and outlet end surface,
Have.

In the twenty-first embodiment, the twenty-second embodiment is deformed so that the platinum group metal coating extends from the surface of the outlet end at a distance of less than 1.5 times the depth of the outlet plug. .. In the twenty-second embodiment, the twenty-second embodiment is modified so that the platinum group metal coating extends at a distance equal to or less than the depth of the outlet plug. In the twenty-third embodiment, the twenty-second to twenty-second embodiments are platinum as the platinum group metal coating moves from the applicator to the end plug end face and the exit end surface of the porous wall. The group metal coating has been modified to have a viscosity that prevents the coating from migrating along the axial length of the porous wall. In the twenty-fourth embodiment, the twenty-third to twenty-third embodiments are modified such that the applicator is selected from the group consisting of brushes, rollers, squeegees and stamp pads. In the twenty-fifth embodiment, in the twenty-fourth to twenty-fourth embodiments, the applicator is modified to be a roller. In the twenty-sixth embodiment, the twenty-fifty-five embodiments further include a length in the range of more than about 10% to about 50% of the wall length from the exit end of the passage. It has been modified to include washcoating an oxidation catalyst washcoat containing a platinum group metal that extends over.

Further features, properties and various advantages of embodiments of the present invention will become more apparent in the context of the accompanying drawings, taking into account the following detailed description, which are the description of the best form considered by the applicant. However, similar reference numbers here indicate similar parts throughout.

FIG. 1 shows the appearance of an embodiment of a wall flow filter substrate having an inlet end and an outlet end. FIG. 2 shows a cross-sectional view of an exemplary embodiment of a plurality of porous walls extending longitudinally from an inlet end to an outlet end of a wall flow filter substrate. FIG. 3 shows an enlarged cross-sectional view of another exemplary embodiment of a plurality of porous walls of a wall flow filter substrate having a plurality of zones formed by a plurality of coatings. FIG. 4 shows an enlarged cross-sectional view of another exemplary embodiment of a plurality of porous walls of a wall flow filter substrate having a plurality of zones formed by a plurality of coatings. FIG. 5 shows an exemplary embodiment of an engine system with a waste treatment system and a urea injector. FIG. 6 shows another exemplary embodiment of an engine system having a waste treatment system, a urea injector and other engine components.

Detailed Description of the Invention Before describing some exemplary embodiments of the invention, it should be understood that the invention is not limited to the details of the configuration or method steps defined in the description below. The present invention can be carried out or performed in different embodiments and in various ways.

Throughout this specification, the terms "one embodiment," "specific embodiment," "various embodiments," "one or more embodiments," or "certain embodiment" are used in the context of embodiments. It means that the particular features, structures, materials or properties described may be included in at least one embodiment of the invention. Thus, expressions that appear in various places throughout the specification, such as "in one or more embodiments," "in a particular embodiment," "in various embodiments," "in one embodiment," or "is. "In an embodiment" does not necessarily refer to the same embodiment of the present invention. Moreover, specific features, structures, materials or properties can be combined in any suitable way in one or more embodiments.

In various embodiments, the coated filter substrates disclosed herein are "zoned", eg, "multi-zoned". These terms are understood to describe a substrate in which at least two different catalytic compositions are located in a particular region (zone) (eg, along the length of the substrate). Multiple zones are generally formed by multiple coatings, where the catalyst coating can be on the surface of the porous wall of the substrate and / or within the pores of the porous wall of the substrate. Such zones can be independently modified to provide one or more specific catalytic actions within each zone. The exhaust gas flow passing from the inlet end to the outlet end of the coated substrate is a different catalytic composition (eg, a layer) as it passes from one zone to the other of the coated substrate. , Or encounter different combinations of catalytic compositions. The "first" zone is usually the zone closest to the entrance of the substrate, and additional zones (eg, second, third, etc.) are downstream thereof.

As used herein, the term "permeate" is used to describe the dispersion of an SCR catalyst and / or an oxidation catalyst in the porous walls of a filter substrate. It means that it penetrates at least most of the hollow area within the wall thickness and is deposited on the inner surface over the wall thickness. In this way the material is dispersed throughout the walls of the filter.

As used herein, the term "local loading" refers to the amount of catalytic material (eg, PGM, SCR catalyst, or oxidation catalyst) present in or on a porous wall. When used to describe, it means the average amount of catalytic material deposited on a wall within a particular zone or zones. That is, the indicated loadings are not averaged over the length of the substrate.

As used herein, "catalytic material carrying amount" refers to the mass of a material containing one or more catalytically active components arranged on and / or in the wall of a catalytic article, wherein the catalytic activity. The components can be platinum group metals (eg Pt, Pd, Rh) and / or transition metals (eg Cu, Fe, Co, Ni, La, V, Mo, W, Mn, Ce, Ag). The catalytic material can further contain a carrier material, on which the (s) catalytically active ingredients are dispersed and / or impregnated therein (s) in the (plurality) catalytically active ingredients). Can be alumina, titania, zirconia, silica, silica / alumina, or a combination thereof.

As used here, the washcoat carrier is g / in ³ , and for every unit volume of the monolithic substrate, all washcoat components (ie, PGM, refractory metal oxide carriers, zeolites, base metals, OSCs, etc.) ) Is defined as the total mass. The amount of PGM supported is g / ft ³ , which is defined as the total mass of all PGM metals (eg Pt + Pd + Rh) in the catalyst per unit volume of the monolithic substrate. Therefore, TWC, DOC, CSF and LNT catalysts that use PGM can be uniquely described by both washcoat loading and PGM loading, while SCR catalysts that do not have a PGM component are washcoated. It can be described only by the amount carried. _{AMO x} catalysts with both SCR catalyst material and PGM can be described by both criteria. As used herein, for PGM catalysts, "loading" refers to the PGM that adheres to the inner and outer surfaces of the (plural) porous walls of the filter substrate after the washcoat has been applied. The actual mass, whereas for SCR catalyst materials, the "supported amount" is the metal attached to the inner and outer surfaces of the (plural) porous walls of the filter substrate after the washcoat has been applied. The actual mass of the accelerator combined with the molecular sieve material. In addition, the localized PGM or washcoat loading can be used to specifically describe the mass / volume of the catalyst component in a particular catalyst zone.

In one or more embodiments, the PGM end coating covers the outlet end surface and the outlet end face of the wall flow filter outlet plug. As used herein, "platinum group metal (PGM)" refers to platinum, palladium, rhodium, ruthenium, osmium and iridium, or combinations thereof, and oxides thereof.

In one or more embodiments, the PGM end coating extends from the outlet end surface at a distance of less than 1.5 times the depth of the outlet plug. The depth used here is the distance at which the outlet plug protrudes into the passage of the base material (filter). That is, the distance from the outlet end face of the outlet plug to the opposite end of the outlet plug (inside the filter). According to one or more embodiments, the outlet plug has a depth in the range of 3 mm to 8 mm and can include depths of 3 mm, 4 mm, 5 mm, 6 mm, 7 mm and 8 mm. In one or more embodiments, the PGM end coating is present in a locally supported amount in the range of ^{about 20 to about 200 g / ft 3.} In one or more embodiments, the platinum group metal end coatings are about 25 to about 200 g / ft ³ , about 30 to about 200 g / ft ³ , about 35 to about 200 g / ft ³ , and about 40 to about 200 g / ft. ³ , present in carrying amounts in the range of about 45 to about 200 g / ft ³ , or about 50 to about 200 g / ft ^3.

According to one or more embodiments, if such a PGM end cover is a wall flow filter, the filter is also catalyzed by a selective catalytic reduction (SCR) catalyst. In one or more embodiments, the coating is axially applied from the outlet end along the porous wall of the wall flow filter by strictly applying the PGM end coating with an applicator for applying the PGM coating paste. Stretching in a direction is restricted or prevented. This avoids overlaps and / or contacts between the SCR catalyst composition and the PGM end coating, and avoids negative interactions between the SCR catalyst composition and the PGM catalyst composition. .. In one or more embodiments, the PGM end cover is an end face that is applied by the applicator only to the outlet end surface and the outlet end face of the plug. In certain embodiments, the applicator can be a brush, roller, squeegee or stamp pad. In a very specific embodiment, the applicator is a roller applicator. A suitable roller applicator can have a structure similar to the rollers used in the application.

In one or more embodiments, the roller applicator can have a cylindrical core with a pile fiber cover fixed to the cylindrical core. Alternatively, the cylindrical core of the roller applicator may be constructed from foamed rubber. It will be appreciated that the rollers can be used to transfer the material (ie, the PGM catalyst composition) from the rollers to the end faces of the wall flow filter. For rollers with a cylindrical core with pile fibers, the fluff length of the pile fibers can specify the depth at which the PGM coating will extend axially along the wall flow filter from the outlet end face. .. It will be appreciated that the longer fluff length of the pile fibers in the rollers will result in a platinum group metal coating that extends deeper into the wall flow filter. Similarly, when using foamed rubber rollers, the softer foamed rubber coats from the outlet end into the wall by applying higher pressure to the roller as the platinum group metal is applied to the outlet end of the filter. Can be penetrated deeper.

Another way to change the degree of axial extension of the PGM end coating into the filter from the outlet end face is to change the viscosity of the PGM end coating when applied to the outlet end of the filter. is there. Generally, in order to minimize or prevent the PGM end coating from entering the porous filter wall by capillary action, the PGM coating is with the slurry used to apply the wash coat, for example by dip coating. In comparison, it should have a relatively high viscosity. The viscosity of the paste should minimize or eliminate capillary movement of the PGM end coating on the porous wall of the filter.

In one or more embodiments, the SCR catalyst and / or other catalyst material (eg, oxidation catalyst) contained within the filter remains substantially on the surface of the porous filter wall (discussed in more detail below). obtain. As used herein, the term "substantially on the surface" is used to describe the dispersion of SCR and / or oxidation catalysts on a porous wall, the catalyst particles of a particular composition. It means that at least most of the above does not enter the area within the wall thickness and is deposited on the inner surface over the wall thickness. Instead, the catalyst material is deposited on the outer surface of the wall, and a minority of catalyst particles penetrates into hollow areas within the wall thickness by about 50% or less, or by about 33% or less, the wall thickness. It penetrates into the hollow region inside, or about 10% or less into the hollow region within the wall thickness. In one or more embodiments, the penetration depth can be varied to optimize the filter back pressure applied in separate washcoat steps and the interaction with the catalytic components, where the SCR The penetration depth of the catalyst and / or oxidation catalyst ranges from about 5% to about 50%, or about 10% to about 40%, or about 5% to about 20%, or about 5% to about 20% of the porous wall thickness. It can be in the range of about 20% to about 35%.

The problem of balancing for some competing reactions can be addressed by wise selection and placement of catalytic materials and components in the exhaust stream, where particulate matter (PM) is a porous wall particulate. _{Nitrogen oxides (NO x} ) can be reduced by the use of filters and can be reduced by selective catalytic reduction (SCR) catalysts with reducing agents (eg urea, NH _{3) and ammonia slip.} ) Can be reduced by an ammonia oxidation catalyst (AMO _x ), which may optionally be included in the system disclosed herein. Specific principles and embodiments of the present invention generally control multi-zone catalytic filter articles, methods of manufacturing multi-zone catalytic filter articles, and emissions in gasoline and diesel engine exhaust streams with multi-zone catalytic filter articles. In terms of methods for this, the emissions treatment systems of various embodiments effectively treat diesel engine exhaust with a single multi-zone catalytic filter article.

To remove soot, multi-zone catalytic filter articles have high filtration performance. Two important considerations for the catalyst coating on the filter are to minimize back pressure and prevent exhaust divergence in the filter / around the catalyst located on the filter. Minimizing back pressure directly leads to fuel savings and, in some cases, engine life. For multi-zone catalytic filter articles that use separate SCR and oxidation catalyst materials to remove NO _{x by NH 3} and CO and HC by O ₂ , the exhaust first begins with the SCR catalyst (ie, "No. 1". It passes through (as a "zone") and then over the oxidation catalyst (ie, as a "second zone"). When the exhaust bypasses the SCR catalyst and is first exposed to oxidizing function, the reducing agent (eg NH ₃ ) is oxidized to NO _x , which is greater than the amount that entered the catalyst before _{NH 3} was added as the reducing agent. _{The NO x} reduction function is impaired until a large amount of NO _{x is released.}

As disclosed herein, the _{integration of NO x} reduction and particulate removal functions into a single catalyst article is achieved by using a wall flow substrate coated with an SCR catalyst composition. In particular, a unique method of applying an SCR catalyst composition to a wall flow substrate to form a substrate that can be used in applications where high filtration efficiency is required is described herein. For example, the substrate formed by this method is suitable for effectively removing particulate matter from exhaust gas in the emission treatment system of the embodiment of the present invention (eg, greater than 80% or 90%). Super or over 99%). The coating method disclosed herein allows the wall flow substrate to be supported at a practical level of the SCR catalyst when mounted in an emission treatment system without causing excessive back pressure over the coated article. become. In one or more embodiments, the SCR catalyst is arranged along the entire length across the wall of the filter and penetrates the entire cross section of the wall. This allows the SCR catalyst to penetrate all filter pores and spread over the maximum filter volume, which minimizes back pressure and ensures that no diversion to the SCR catalyst occurs.

In one or more embodiments, in addition to the end coating of the platinum group metal, an oxidation catalyst washcoat is dispersed across the wall of the filter along at least a portion of the length of the filter, cross-section of the wall. It has invaded the whole. This allows the oxidation catalyst to penetrate the filter pores and spread over the maximum filter volume, which minimizes back pressure and ensures that no diversion to the oxidation catalyst occurs.

In one or more embodiments, the oxidation catalyst is dispersed across the wall of the filter along at least a portion of the length of the filter, where the oxidation catalyst penetrates the entire cross section of the wall and the oxidation catalyst. Dispersed on the surface of the wall of the filter along at least a portion of the length of the filter, where the oxidation catalyst has not penetrated the entire cross section of the wall. This causes most of the oxidation catalyst to be predominantly on the surface of the filter, with a minority of catalyst particles getting into the wall thickness by about 50% or less along part of the length of the filter wall, or Approximately 33% or less within the wall thickness, or approximately 10% or less within the wall thickness.

In various embodiments, when observed axially along the length of the porous wall of the filter, the different zones of the catalytic filter disclosed herein are changes in the composition of the catalyst coating, changes in the amount of catalyst coating carried. , Or both.

In one or more embodiments, the oxidation catalyst (as the "second zone") is dispersed above the walls of the (s) outlet channels. In some embodiments, the oxidation catalyst forms a layer at the top of the wall, above the SCR catalyst (as the "first zone") dispersed throughout the wall. Oxidation catalysts allow some gas passages to pass through the wall beneath them, but the condition is sufficient SCR in the wall to remove _{NO x before the gas intersecting the oxidation catalyst.} There is a catalyst.

One or more embodiments of the present invention relate to a catalytic particulate filter having a plurality of longitudinally extending passages formed by a longitudinally extending porous wall, which is the passage and the inlet end and. Separate and specify the shaft length extending from the outlet end. This passage has an entrance passage that is open at the entrance end and closed at the exit end, and an exit passage that is closed at the entrance end and open at the exit end. As used herein, the terms "inlet end" and "outlet end" are intended and accepted to describe the path of exhaust gas through the catalytic article, where untreated exhaust gas is used. Passes through the catalyst article at the outlet end, and the treated exhaust gas exits from the outlet end of the catalyst article. In various embodiments, the outlet end of the catalyst article is on the opposite side of the inlet end.

In various embodiments, the SCR catalyst composition is located within the porous wall of the wall flow filter and / or on the wall of the inlet passage extending from the inlet end to less than the total axial length of the wall flow filter. Here, the SCR catalyst composition has a molecular sieve and a transition metal, and the oxidation catalyst containing PGM is placed in the porous wall of the wall flow filter and / or from the outlet end, on the entire axis of the wall flow filter. It is located on the wall of the exit passage that extends less than the length. In one or more embodiments, some of the oxidation catalysts can penetrate into the filter wall and may be mixed with the SCR catalyst. In some embodiments, the catalyst applied to the inlet or outlet channel can form a thin washcoat layer above the inlet or outlet plug in the inlet or outlet channel.

The principles and embodiments of the present invention relate to a catalytic particulate filter comprising a substrate having a porous wall and at least three catalytic zones along the length of the porous wall, wherein at least three catalytic zones are present. They can have a first SCR catalyst, an oxidation catalyst (eg PGM catalyst) and a second SCR catalyst, respectively.

Principles and embodiments of the present invention also generally relate to methods of reducing exhaust gas from a lean burn engine, where the exhaust gas flows through an embodiment of the catalytic particulate filter described herein, where CO. , HC, NO _x , soot, NH ₃ and H ₂ S, preferably at least 5 of them, preferably CO, HC, NO _x , soot, NH ₃ and H ₂ S, all 6 by catalytic particulate filter. Partially removed from exhaust gas. Principles and embodiments of the present invention also generally _{relate to the integration of NO x} reduction and particulate removal functions into a single catalytic article, which uses a wall flow substrate coated with an SCR catalytic composition. Achieved by.

Particulate Filter In one or more embodiments, the particulate filter has a plurality of porous walls having a length extending longitudinally to form parallel passages extending from the inlet end to the outlet end. Many passages here are entrance passages that are open at the entrance end and closed at the exit end, and many passages that are different from the entrance passage are closed at the entrance end and exit. It is an exit passage that is open at the end. In various embodiments, these passages are closed with a plug, where the plug is about 1/4'' long (and, when described in the context of a filter, the corresponding "depth". ") Can have. The open frontal area can have 50% to 85% of the surface area, the wall thickness of the cell is 4 to 20 mils, where 1 mil is 0.001 inch. In one or more embodiments, the porous filter has an inlet end that allows the gas to enter the inlet passage and an outlet end that allows the gas to exit the outlet passage, where the gas is parallel. By moving through a porous wall that forms a clear passage, it passes from the inlet passage to the exit passage.

In one or more embodiments, the porous wall is in the range of about 40% to about 75%, or in the range of about 40% to about 60%, or in the range of about 50% to about 70%, or about 50% to about. It has a porosity in the range of 65%, or about 60% to about 70%, or about 55% to about 65%. In various embodiments, the porous wall has a porosity in the range of about 60% to about 65%. In one or more embodiments, the average pore size of the porous wall ranges from about 10 μm to about 30 μm, about 10 μm to about 25 μm, or about 20 μm to about 25 μm. In various embodiments, the average pore size of the porous wall ranges from about 15 μm to about 25 μm.

In various embodiments, an inlet or outlet "extending" coating means that the coating begins at one end of the wall and proceeds along the wall length toward the opposite end. Shown. Or here, for example, a covering feature that is on the surface can start at a distance from the actual inlet opening, and a covering feature that "extends from" the inlet or outlet end is that the covering feature is wall length. Indicates that the vehicle travels along the opposite end toward the opposite end. For example, the second zone, which lies between the first and third zones, extends over a percentage of the wall length from the entrance or exit ends, but does not start at the entrance or exit ends, on the surface. Can include a coating in, which can indicate the direction in which the coating extends.

Selective Catalytic Reduction (SCR) Catalyst In one or more embodiments, the SCR catalyst contains a molecular sieve. In various embodiments, the molecular sieve can have a zeolite scaffold, and the zeolite scaffold can have a ring size of 12 or less. In one or more embodiments, the zeolite backbone material has double 6-membered ring (d6r) units. In one or more embodiments, the zeolite backbone materials are AEI, AFT, AFX, CHA, EAB, EMT, ERI, FAU, GME, JSR, KFI, LEV, LTL, LTN, MOZ, MSO, MWW, OFF, SAS, It may be selected from SAT, SAV, SBS, SBT, SFW, SSF, SZR, TSC, WEAR, and combinations thereof. In various embodiments, the zeolite backbone material may be selected from AEI, CHA, AFX, ERI, KFI, LEV, and combinations thereof. In various embodiments, the zeolite backbone material may be selected from AEI, CHA, and AFX. In various embodiments, the zeolite backbone material is CHA.

In various embodiments, the SCR catalyst further contains a metal, which can be a base metal. In various embodiments, the SCR catalyst is facilitated by a metal selected from Cu, Fe, Co, Ni, La, Ce, Mn, V, Ag and combinations thereof. In various embodiments, the SCR catalyst is facilitated by a metal selected from Cu, Fe, Ag and combinations thereof. In various embodiments, the selective catalyst reduction catalyst is facilitated by Cu and / or Fe.

In one or more embodiments, the zeolite backbone material is copper or iron-promoted CHA. In one or more embodiments, a copper or iron-promoted CHA-structured molecular sieve can be mixed with a plurality of platinum group metals impregnated with alumina and / or silica / alumina particles to form a slurry. it can.

In one or more embodiments, the SCR catalyst has a first carrier amount (eg, in the zone at the inlet), and any second carrier amount (eg, where the SCR catalyst is mixed with PGM, and). / Or in the zone at the exit), where the first carrier may be ^{in the range of about 0.5 g / in 3} to about 3 g / in ³ , and the second carrier is. It may be in the range of about 0.5 g / in ³ to about 2.5 g / in ³ , where the second carrier may be the same as or different from the first carrier. In various embodiments, the amount of support that can occur in the overlapping zones can range from ^{about 1.0 g / in 3} to about 5.0 g / in ^3.

Non-limiting examples of SCR catalysts are copper-promoted CHA zeolites with molar ratios of silica to alumina in the range of about 10 to about 100, especially about 10 to about 75, and even about 10 to about 60. It is a skeletal material. In various embodiments, at least about 0.5 g / in ³ of the SCR composition, particularly about 1.0 to about 2.0 g / in ³ of the SCR composition, can be placed on the porous wall of the filter. .. In various embodiments, the first carrier of the SCR catalyst in the second catalyst zone can be in the range of ^{about 0.5 g / in 3} to about 2 g / in ^3.

Oxidation Catalysts Principles and embodiments of the present invention relate to oxidation catalysts containing PGM located on / in at least one zone of a catalytic particulate filter. In one or more embodiments, the oxidation catalyst PGM may be selected from platinum, palladium, rhodium, ruthenium, osmium and iridium, or a combination thereof. In various embodiments, the PGM of the oxidation catalyst may be selected from platinum, palladium, or a combination thereof.

In one or more embodiments, the oxidation catalyst contains at least one platinum group metal on the plurality of particles, and the plurality of particles of the oxidation catalyst are compositions of alumina, titania, zirconia, silica, silica / alumina. , Or a combination thereof. In one or more embodiments, the PGM may be impregnated within alumina, titania, zirconia, silica, and / or silica / alumina particles by an incipient wetness technique, followed by 400 ° C. and up. Heat treated at 600 ° C. In various embodiments, the amount of PGM supported on the length of the porous wall into which the oxidation catalyst slurry penetrates ranges from about 0.1 g / ft ³ to about 50 g / ft ³ . In various embodiments, the amount of PGM supported on the length of the porous wall into which the slurry penetrates ranges from about 0.1 g / ft ³ to about 50 g / ft ³ , or from about 1 g / ft ³ to about 50 g. It is in the range of / ft ^3. In one or more embodiments, the amount of PGM supported in the second catalyst zone ranges from about 0.1 g / ft ³ to about 50 g / ft ³ , or from about 1 g / ft ³ to about 50 g / ft ³ . obtain.

In one or more embodiments, the oxidation catalyst is a PGM slurry having D90 <3 microns, or D90 <5 microns, or D90 <10 microns, or D90≈5-7 microns. In various embodiments, the copper- or iron-promoted CHA-structured molecular sieves may be mixed with an oxidation-catalyzed slurry.

PGM end coating In one or more embodiments, a platinum group metal end coating covering the outlet end surface and the outlet end surface of the wall flow filter plug can be provided, which coating is from the outlet end surface to the outlet plug. It extends at distances less than 1.5 times its length and has a local platinum group metal carrying amount in the range of ^{20-200 g / ft 3.} In one or more embodiments, the platinum group metal end coating is applied only to the outlet end surface and the outlet end face of the plug by applying PGM to the end face using an applicator to transfer the coating. According to one or more embodiments, the applicator is selected from brushes, rollers, squeegees or stamp pads. According to one or more embodiments, the PGM end coating is applied as a coating with a higher viscosity than the conventional slurry used to apply the washcoat. In one or more embodiments, the PGM end coating has a paste consistency with a viscosity that prevents the coating from axially migrating along the porous walls of the filter when applied.

Manufacturing Method The principles and embodiments of the present invention also relate to a method of manufacturing a catalytic particulate filter having at least two catalyst zones or at least three catalyst zones, wherein the catalyst zones are at least two or at least three, respectively. It is formed using a catalyst coating.

In one or more embodiments, the oxidation catalyst is introduced into the outlet end of a plurality of parallel passages formed by a plurality of porous walls closed by a plug at the inlet end opposite the outlet end. Oxidation catalyst particles penetrate across the porous wall, where the length of the porous wall that the oxidation catalyst penetrates is about 10 of the wall length extending from the exit end of the passage. It is in the range of about 80%, or in the range of about 10% to about 70%, or in the range of about 60% to about 70%.

In one or more embodiments, the SCR catalyst containing the plurality of particles is an inlet end of a plurality of parallel passages formed by a plurality of porous walls closed by a plug on the outlet side opposite to the inlet side. It can be introduced into the moiety, where the particles of the SCR catalyst penetrate over the porous wall, where the length of the porous wall into which the particles of the SCR catalyst penetrate extends from the inlet end of the passage. It ranges from about 20% to about 100%, about 50% to about 100%, about 50% to about 80%, or about 60% to about 70% of the wall length.

In various embodiments, the oxidation catalyst can contain multiple particles, eg, as a slurry of inorganic carrier material coated and / or impregnated with PGM, where the oxidation catalyst can be an ammonia oxidation catalyst.

In one or more embodiments, the oxidation catalyst is introduced into the exit ends of the plurality of parallel passages before the SCR catalyst is introduced into the inlet ends of the plurality of parallel passages. In various embodiments, the SCR catalyst is introduced into the inlet ends of the plurality of parallel passages before the oxidation catalyst is introduced into the outlet ends of the plurality of parallel passages.

In one or more embodiments, the particles of the oxidation catalyst, along with the particles of the SCR catalyst, are interspersed in at least a portion of the plurality of porous walls, where the particles of the SCR catalyst and the oxidation catalyst are on the surface and. / Or scattered in the dead space of the porous wall. Therefore, in some embodiments, it has a zone containing only the SCR catalyst and a zone having SCR catalysts and oxidation catalysts (for example, PGM metal) scattered on and / or in the porous wall. A base material is prepared. In various embodiments, the porosity of the porous wall ranges from about 60% to about 65%.

In one or more embodiments, the PGM end cover may be located on the outer surface of the plug on the exit side of the parallel passage. In various embodiments, the PGM end coating is in the range of about 5% of the wall length extending from the outlet end of the outlet passage, or about 5% or less, about 3% or less, about 2 on the surface of the porous wall. It may be coated in the range of% or less, or about 1% or less, or twice or less of the outlet plug length.

In a non-limiting example of a method for coating a wall flow substrate with an SCR catalytic composition and / or an oxidation catalyst, the substrate is a portion of the catalyst slurry of solid particles, perpendicular to the liquid, on top of the substrate. May be immersed so that is located just above the surface of the slurry. The sample is left in the slurry for about 30 seconds. The substrate is removed from the wall flow substrate by removing the substrate from the slurry, draining excess slurry from the flow path and then blowing compressed air (against the direction of permeation of the slurry). Depending on the pore size of the filter, the average pore size of the SCR-catalyzed slurry, and prior to the processing step, the SCR-catalyzed slurry does not interfere with the pores to the extent that excessive back pressure occurs in the final substrate. As such, it can deposit on and / or penetrate into the porosity of the filter. In various embodiments, the oxidation catalyst slurry can be deposited on and / or penetrate into the porous wall of the filter.

In various embodiments, the second SCR catalyst can be applied to the inlet or outlet channels to deposit on and / or penetrate into the porous walls of the filter. In various embodiments, the carbon dioxide catalyst can be applied to the inlet and / or outlet channels to deposit on the surface of the porous wall of the filter.

In one or more embodiments, the method of making a catalytic suit filter is
The process of coating a catalytic suit filter containing multiple porous walls that extend longitudinally to form parallel passages extending from the inlet end to the outlet end, where numerous passages are at the inlet end. An entrance passage that is open at and closed by an exit plug at the exit end, and a number of passages are exit passages that are closed by an entrance plug at the entrance end and open at the exit end. The plug has a depth and an outlet plug end face, the outlet end defining the outlet end surface including the outlet plug end face.
including. Coating the catalytic soot filter involves wash-coating the SCR catalytic washcoat onto the porous wall of the particulate filter, and contacting the outlet plug end face and outlet end surface with an applicator having a PGM coating. The PGM coating is transferred from the applicator to the outlet plug end face and the outlet end surface. The SCR washcoat can be applied first, and then the platinum group metal coating applied by the applicator can be applied second. Alternatively, the order of coating application can be reversed.

In one or more embodiments, the PGM end coating extends from the outlet end surface at a distance of less than 1.5 times the depth of the outlet plug. In one or more embodiments, the PGM end cover extends at a distance equal to or less than the depth of the outlet plug. In one or more embodiments, the PGM end covering is the PGM end coating as it moves from the applicator to the outlet plug end face and the exit end surface of the porous wall, which coating is the axial length of the porous wall. It has a viscosity that prevents it from migrating along. In one or more embodiments, the applicator is selected from the group consisting of brushes, rollers, squeegees and stamp pads. In one or more embodiments, the method also includes washcoating a PGM washcoat extending from the exit end of the aisle over a length ranging from more than about 10% to about 50% of the wall length. it can.

Catalytic Exhaust Systems and Emission Reduction Methods The principles and embodiments of the present invention also relate to catalytic exhaust systems having at least one catalytic particulate filter, as described herein. In various embodiments, the catalytic exhaust system comprises a catalytic particulate filter according to the present disclosure and one or more additional components for reducing some proportion of gaseous pollutants and particulate matter. Can be done.

In one or more embodiments, a urea injector (also referred to as a reducing agent supply system) _{injects NO x} reducing agent into the exhaust stream upstream of the catalytic particulate filter into the catalytic particulate filter. It may be provided to facilitate the operation of the incorporated SCR catalyst. As disclosed in US Pat. No. 4,963,332 (US Pat. No. 4,963,332), which is incorporated herein by reference in its entirety for all purposes. _{NO x} located upstream and downstream of the catalytic converter can be detected and the pulsed supply valve can be controlled by upstream and / or downstream signals. Another configuration, the system disclosed in US Pat. No. 5,522,218 (US Pat. No. 5,522,218), which is incorporated herein by reference in its entirety for all purposes. The pulse width of the reducing agent injector can be controlled from a map of the sensor valve and / or exhaust gas temperature and engine operating conditions such as engine speed (rpm), transmission gear and engine speed. Reducing agent pulse weighing systems as described, for example, in US Pat. No. 6,415,602 (US Pat. No. 6,415,602) can also be used, the discussion of which is by reference herein for all purposes. The whole is incorporated into.

In various embodiments, the exhaust system can have an exhaust manifold, an exhaust pipe (or a down pipe, or a Y-tube), a muffler and a tail pipe. The catalytic exhaust system may be inserted into the exhaust system with a Y-tube and / or exhaust pipe to process the exhaust from the internal combustion engine in front of the gas exiting the tailpipe to the atmosphere.

In one or more embodiments, the catalyst exhaust system has a monolithic catalytic substrate having a length, width, height, and a noble metal carrier. In various embodiments, the monolithic catalytic substrate can have the following shapes: a cylinder with a diameter and length that defines the cross-sectional area; a major axis and a uniaxial, and a length that defines the cross-sectional area. An elliptical shape with a sword; or an oval shape with a spindle and lateral diameter and length that defines the cross-sectional area; where the monolithic catalytic substrate is a noble metal carrier to provide the intended level of catalytic activity. Have a quantity. In one or more embodiments, the noble metal carrier can contain one or more platinum group metals, one or more base metals, one or more noble metal oxides and / or base metal oxides, or a combination thereof. ..

In various embodiments, the catalyst exhaust system is a two-way catalyst, a three-way catalyst (TWC) (mainly used in chemically-quantitative combustion gasoline engines), a diesel oxidation catalyst (DOC) (mainly in lean combustion diesel engines). (Used in), selective catalytic reduction (SCR) catalyst, lean nitrogen oxide catalyst (LNC), ammonia slip catalyst (ASC), ammonia oxidation catalyst (AMOx), NOx absorber (NOx storage / release catalyst (NSR)) (Said), and lean NOx traps (LNT), diesel particulate filters (DPF), gasoline particulate filters (GPF), partial oxidation catalysts (POC), and catalytic soot filters (CSF), and combinations thereof. be able to. In various embodiments, the catalyst exhaust system is selected from diesel oxidation catalyst (DOC), lean NOx trap (LNT), passive NOx absorber (PNA), SCR catalyst associated with ammonia injection, and ammonia oxidation catalyst (AMOx). It can contain (but not be limited to) one or more additional components that are to be used.

In various embodiments, the monolithic catalytic substrate may be coated with at least one washcoat layer containing one or more catalytic materials, which are platinum group metals, base metals, and metal oxides. It may also be selected from the substrates stored in the case. In one or more embodiments, the catalytic transformant can have a monolithic catalytic substrate housed in a case with inlets and outlets, where the shell may be operably related and. It may be housed in a housing that may communicate fluidly with the exhaust system of the internal combustion engine.

1 and 2 show a typical wall flow filter substrate 10 (also referred to as a wall flow filter) having a plurality of passages 12. These passages are formed by the inner wall 13 of the filter base material and are surrounded in a tubular shape. FIG. 1 shows the appearance of an embodiment of a wall flow filter substrate having an inlet end 14 and an outlet end 16. The alternative flow path is blocked by the inlet plug 18 (shown in black) at the inlet end, blocked by the outlet plug 20 at the outlet end, and the checkers facing each other at the inlet end 14 and the outlet end 16 of the substrate. Form a board-like pattern.

FIG. 2 shows a cross-sectional view of an embodiment of a plurality of porous walls extending in the longitudinal direction from the inlet end portion to the outlet end portion of the wall flow filter base material. A partial cross-sectional view of an embodiment of a plurality of porous walls 13 extending longitudinally from an inlet end 14 to an outlet end 16 and forming a plurality of parallel passages 12 is shown. The gas stream 22 (shown as an arrow) is porous, entering through the end of an open, unobstructed inlet passage 24 and stopping at the end closed by the outlet plug 20 to form a passage to the outlet passage 26. It is diffused through the wall 13. The gas stream 22 exits the filter by flowing through the end of the open, unobstructed outlet passage 26 and stops at the end closed by the inlet plug 18. The inlet plug 18 prevents the gas from flowing backward from the outlet passage to the inlet end of the filter, and the outlet plug 20 prevents the gas from re-entering the inlet passage from the outlet end. In this way, many passages are entrance passages that are open at the entrance end and closed at the exit end, and many passages are exits that are closed at the entrance end and open at the exit end. It is a passage, where the exit passage is a different passage from the entrance passage.

FIG. 3 shows an enlarged cross-sectional view of an exemplary embodiment of a plurality of porous walls of a wall flow filter substrate having a plurality of zones. The catalyst article shown herein has a wall flow filter 10 having a plurality of longitudinally extending passages 12 formed by a defined longitudinally extending porous wall 13 that separates passages 24 and 26. and, wherein the wall has an axial length extending between the wall-flow filter inlet end 14 and outlet end 16 having an "L _F" length. In various embodiments, the porous wall has substantially uniform porosity as a whole. The passages 24 and 26 are an entrance passage 24 that is open at the entrance end 14 and closed at the exit end 16, and an exit passage that is closed at the entrance end 14 and is open at the exit end 16. It has 26 and. In various embodiments, the outlet plug 20 has a depth between the arrow 25 and the outlet plug end face 27. The outlet end 16 of the wall 13 defines the outlet end surface 29.

FIG. 4 shows an enlarged cross-sectional view of another exemplary embodiment of a plurality of porous walls of a wall flow filter substrate having a catalyst at least on the surface of the wall in the front zone. In one or more embodiments, the exhaust gas stream 22 enters the inlet passage 24 and flows towards the outlet end 16 of the wall filter 10. The gas can take various paths 54, 56, and / or 58 through the filter 10, including passing from the inlet passage 24 to the outlet passage 26 through the 54 porous wall 13, where the gas is. Can exit via the outlet end 16 of the filter. In another flow passage 56, a partial amount of exhaust gas 22 can continue to the passage 54 through the porous filter wall 13 containing the SCR catalyst 40, and then comes into contact with the oxidation catalyst 45 as it exits the filter. For another alternative waypoint 58, a partial amount of exhaust gas 22 can be diffused through the porous wall 13 containing the SCR catalyst 40 and through the oxidation catalyst 45.

In various embodiments, the depth of the inlet plug 18 and / or the outlet plug 20 is in the range of about 3 mm to about 8 mm, or in the range of about 6 mm to about 7 mm, or about 6.35 mm (0.25 inch). .. In various embodiments, the inlet plug 18 and / or the outlet plug 20 extends into the inlet passage 24 and / or the outlet passage 26, respectively, over its entire length, where the outer surface of the plugs 18 and 20 is the wall flow filter 10. It is substantially flushed by the end of the porous wall 13.

In one or more embodiments, the PGM end coating 51 may be coated on the outlet end surface 29 and the outlet plug end surface 27 of the plug. In one or more embodiments, the PGM coating 51 into the outlet end of the outlet passage 26 is about 5% or less of the wall length, or about 3% or less of the wall length, or 1% or less of the wall length. , May grow. In various embodiments, the PGM end cover 51 may extend within the outlet end of the outlet passage 26 with a length in the range of about 1 mm to about 2.5 mm. In various embodiments, the PGM end cover 51 is about 1.5 times as long as the depth of the outlet plug or about 1 times the depth of the outlet plug into the outlet end of the outlet passage 26. It may extend in length.

FIG. 3 shows an enlarged cross-sectional view of another exemplary embodiment of a plurality of porous walls of a wall flow filter substrate having a plurality of zones formed by a plurality of coatings, wherein at least some catalyst coatings are shown. May be on the surface of the porous wall of the wall flow filter. In one or more embodiments, the exhaust gas stream 22 enters the inlet passage 24 and flows towards the outlet end 16 of the wall filter 10. The gas can take various paths 54, 56, and / or 58 through the filter 10, including passing from the inlet passage 24 to the outlet passage 26 through the 54 porous wall 13, where the gas is. Can exit via the outlet end 16 of the filter. In the specific flow passage 54, the exhaust gas can flow on the inlet side surface of the porous wall 13 through the second SCR catalyst 43, and the first SCR catalyst 40 impregnated in the porous wall 13. Can flow through. In another flow passage 56, a partial amount of exhaust gas 22 can continue to the passage 54 through the porous filter wall 13 containing the first SCR catalyst 40 and then upon exiting the filter, the porous filter wall. It comes into contact with the oxidation catalyst 45 on the outlet side surface of 13. For another alternative waypoint 58, a partial amount of exhaust gas 22 can be diffused through the porous wall 13 containing the first SCR catalyst 40 and through the oxidation catalyst 45.

In one or more embodiments, each catalyst component penetrates the porous wall of the catalyst substrate and the catalyst components are interspersed within the wall. In various embodiments, the first SCR catalyst is mixed with the oxidation catalyst within the porous wall. In various embodiments, the SCR catalyst has penetrated the porous wall and most of the oxidation catalyst is on the surface of the porous wall impregnated with SCR. In various embodiments, the majority of the oxidation catalyst resides on the surface of the porous wall impregnated with SCR and is sandwiched between the porous wall in which the SCR catalyst has penetrated and the upper layer of the SCR catalyst. .. In various embodiments, the oxidation catalyst coating in the second zone is on the surface of the porous wall and the oxidation catalyst coating in the third zone is between the first SCR catalyst coating and the second SCR catalyst coating. It is sandwiched between.

FIG. 5 is an example of an engine system having an effluent treatment system 140, an ammonia precursor supply line 148, an air supply line 149, and a urea injector with a mixing station 146 connected to the effluent treatment system by fluid communication. Embodiment is shown. As can be seen from FIG. 12, exhausts containing gaseous pollutants (including unburned hydrocarbons, carbon monoxide and NO _x ) and particulate matter are connected from the engine 141 as described herein. It is carried to the catalytic particulate filter 143 through section 142. After the catalytic particulate filter 143, the exhaust gas exits the system via the tailpipe 144. Downstream of the engine 141, a reducing agent, such as urea, can be injected into the exhaust stream as a spray through a nozzle (not shown). The aqueous urea shown on one line 148 can serve as an ammonia precursor that can be mixed with air in another line 149 at the mixing station 146. Valve 145 can be used to weigh the exact amount of aqueous urea that is converted to ammonia in the exhaust stream. The exhaust stream, along with the added ammonia, is carried to a multifunctional catalytic particulate filter 143, where NH ₃ can interact with the SCR catalyst.

The connection 142 may not be needed if no additional components are used in front of the catalytic particulate filter 143. In these embodiments, the catalytic particulate filter 143 is directly connected to the engine 141. The distance between the engine and the catalyst can be very short, which results in a so-called "proximity" catalyst arrangement. Alternatively, the distance from the engine to the catalyst may be longer, which results in an "underfloor" configuration.

FIG. 6 shows another exemplary embodiment of an engine system having a waste treatment system, a urea injector and other engine components. As shown in FIG. 6, some embodiments of the processing system have one or more distinct components 147. These optional components 147 can include one or more of diesel oxidation catalysts, lean NO _x traps, partial NO _x adsorbents, or three-way catalysts. Depending on the desired level of NO _x removal, an additional SCR catalyst 150 may be located upstream of the multifunction catalytic particulate filter 143. For example, an additional SCR catalyst may be placed upstream of the soot filter on a monolithic honeycomb flow through a substrate or ceramic foam substrate. Depending on the desired level of NO _x removal, an additional SCR catalyst 152 may be located downstream of the multifunction catalytic particulate filter 143 and may also have an _{additional AMO x catalyst.} In these various embodiments, the use of a multifunctionally coated SCR soot filter further achieves the total volume reduction of the catalyst required to meet the _{NO x reduction goals.} Depending on the desired level of hydrocarbon removal, additional oxidation catalysts can be placed upstream of exhaust component 147 or downstream of exhaust component 152. In various embodiments, the oxidation catalyst will not include component 150. This is because the injected urea is oxidized to NO _x .

Catalyst Examples The non-limiting examples disclosed herein describe a particular spatial arrangement and the amount of catalyst material carried on the catalyst substrate. The present invention is not limited to the arrangement configurations, structural details referred to, or the method steps defined in the following description of this example, the invention is possible in other embodiments, and in various ways. It should be understood that it can be done or implemented.

Sample production for samples 1-6:
Non-limiting examples 1-6 are summarized in Table 1. The matrix of these examples involves a "face painting" of the catalytic material. Unlike washcoats, where the catalyst material penetrates into the porous medium of the filter, end face application is applied only on the end face (or exposed end) of the filter by applying the catalyst paste with a brush or roller. Therefore, the catalytic material is not expected to enter the filter beyond the filter plug by capillary action. When the washcoat is applied to the edge surface by immersing the edges of the substrate in a washcoat slurry, the coating extends axially from the edges towards the interior of the substrate by capillary force. It can be difficult to tightly control the length of the coating applied by the washcoat technique. However, by using end face coating techniques with an applicator, such as a roller, and by using a coating with viscosity (which is the viscosity of the paste, which is higher than the viscosity of the washcoat slurry), the outlet of the wall flow substrate. The depth or length of the zone applied on the edge can be tightly controlled. For Examples 2, 4 and 6, a Pd end face coating coating paste _{was prepared by first impregnating an Al 2} O ₃ carrier with a Pd nitrate solution to bring the Pd loading to 5.5% by weight. The Pd / Al ₂ O ₃ powder was then suspended in water supplemented with 5% alumina binder and 2.5% Zr acetate. The final coating paste has a solid content of 9%. The amount of Pd supported for end face coating shown in Table 8 is based on the entire filter volume. However, the catalyst loading for other coatings is based on the applied zone (local loading). Drying (1 hour at 110 ° C.) and calcination (2 hours at 450 ° C.) were performed after each coating (including end face coating).

Samples 1-6 Performance Evaluation Examples 1-6 samples _{1~6, NO 500ppm, NH 3 550ppm} , CO 500ppm, O 2 10%, H 2 O 5%, CO 2 5%, from N ₂ of residues Evaluated in another feed consisting of. Since this feed contained CO, no separate CO test was performed. Table 2 _{summarizes the NO x} conversion rates for samples 1-6. Sample 1 is SCR. _{Samples 2 and 5 show comparable or slightly higher NO x} conversion rates at all temperatures compared to the SCR reference (Sample 1). Other samples show a slightly lower NO _x conversion at 500 ° C. Table 3 _{compares NH 3} conversion rates. _{All samples showed significantly higher NH 3} conversion rates compared to SCR references, with sample 4 being the most active. Table 4 shows the peak N ₂ O formation and the CO conversion rate at 500 ° C. _{Peak N 2} O formation for all samples _{is comparable to peak N 2} O formation with reference to SCR (6-8 ppm). The CO conversion rate with reference to SCR is close to 0 at 500 ° C., while Samples 3, 4 and 6 are much more active with respect to CO conversion rate (49-76%).

Although the present invention has been described with reference to specific embodiments, it should be understood that these embodiments are merely a description of the principles and applications of the invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the methods and devices of the present invention as long as they do not deviate from the ideas and scope of the present invention. Accordingly, the present invention is intended to include variations and variations within the scope of the appended claims and their equivalents.

Claims (24)

It is a catalytic particulate filter
Multiple porous walls extending longitudinally to form parallel passages extending from the inlet end to the exit end, where a number of passages are open at the entrance end and at the exit end. An inlet passage closed by an outlet plug, many passages are outlet passages closed by an inlet plug at the entrance end and open at the outlet end, and the outlet plug is a depth and outlet plug end face. The outlet end defines the outlet end surface of the outlet passage, including the outlet plug and the outlet plug end face.
The selective catalyst reduction catalyst applied to the porous wall of the particulate filter, and the platinum group metal end coating covering the outlet end surface and the outlet end surface of the plug, the platinum group metal end coating is from the outlet end surface to the outlet plug. It extends at a distance less than 1.5 times the depth of, and has a locally supported amount of platinum group metal in the range of ^{706.3 to 7063.0 g / m 3} (20 to 200 g / ft ^3).
It has a platinum group metal end coating is an end applied only to the outlet end face of the outlet end surface and the plug by the applicator, catalytic particulate filter. The catalytic particulate filter according to claim 1, wherein the plug at the outlet end has a length in the range of 3 mm to 8 mm. Applicator, brush, roller, is selected from the group consisting of a squeegee and stamp pads, catalytic particulate filter according to claim 1, wherein. Applicator is a roller, catalytic particulate filter according to claim 1, wherein. The catalytic particulate filter according to claim 1, wherein the platinum group metal end coating extends from the surface of the outlet end at a distance equal to or less than the depth of the outlet plug. The catalytic particulate filter according to claim 1, wherein the supported amount of the platinum group metal end coating is in the range of 706.3 to 5287.2 ^{g / m 3} (20 g / ft ^{3 to 150 g / ft 3).} The catalytic particulate filter according to claim 1, wherein the platinum group metal for edge coating is palladium. The catalytic particulate filter according to claim 1, further comprising an oxidation catalyst washcoat comprising a platinum group metal extending from the outlet end of the passage to a depth in the range of 10% to 50% of the wall length. The catalytic particulate filter according to claim 1, wherein the selective catalytic reduction catalyst coating extends over the entire length of the porous wall. The catalytic particulate filter according to claim 1, wherein the selective catalyst reduction catalyst coating penetrates into the porous wall. The catalytic particulate filter according to claim 8 , wherein the selective catalyst reduction catalyst overlaps with the oxidation catalyst wash coat. The catalytic particulate filter according to claim 8 , wherein the oxidation catalyst wash coat overlaps with the selective catalyst reduction catalyst. The catalytic particulate filter according to claim 1, wherein the selective catalyst reduction catalyst has a molecular sieve promoted by a base metal. The catalytic patty according to claim 1, wherein the selective catalyst reduction catalyst is a zeolite skeleton material promoted with a metal selected from Cu, Fe, Co, Ni, La, Ce, Mn, V, Ag and combinations thereof. Curated filter. The catalytic particulate filter according to claim 1, wherein the selective catalyst reduction catalyst is a zeolite having a CHA skeleton promoted by Cu, Fe and a metal selected from a combination thereof. The catalytic particulate filter according to claim 1, wherein the platinum group metal end coating is only the platinum group metal coating on the catalytic particulate filter. A lean-burn engine exhaust system having a diesel oxidation catalyst upstream from the catalytic particulate filter according to any one of claims 1 to 16. A lean-burn engine exhaust system having a lean NOx trap upstream from the catalytic particulate filter according to any one of claims 1 to 16. A method of manufacturing a catalytic soot filter.
The process of coating a catalytic suit filter containing multiple porous walls that extend longitudinally to form parallel passages extending from the inlet end to the outlet end, where numerous passages are at the inlet end. An entrance passage that is open at and closed by an exit plug at the exit end, and a number of passages are exit passages that are closed by an entrance plug at the entrance end and open at the exit end. The plug has a depth and an outlet plug end face, and the outlet end defines the outlet end surface including the outlet plug end face.
Coating the catalytic soot filter here involves wash-coating the selective catalytic reduction catalyst washcoat onto the porous wall of the soot filter, and coating the outlet plug end face and outlet end surface with a platinum group metal. The step of contacting with the containing applicator, whereby the platinum group metal coating is transferred from the applicator to the outlet plug end face and the outlet end surface.
Only containing platinum group metal end coating extends a distance less than the exit end surface is 1.5 times the depth of the outlet plug, and the local loading of platinum group metals, 706.3 The method for producing , which has a range of ~ 7063.0 g / m ³ (20 to 200 g / ft ^3). 19. The method of claim 19, wherein the platinum group metal coating extends at a distance equal to or less than the depth of the outlet plug. As the platinum group metal coating moves from the applicator to the end plug end face and the exit end surface of the porous wall, the platinum group metal coating transfers this coating along the axial length of the porous wall. 19. The method of claim 19, which has a viscosity to prevent. 19. The method of claim 19, wherein the applicator is selected from the group consisting of brushes, rollers, squeegees and stamp pads. 19. The method of claim 19, wherein the applicator is a roller. 19. The method of claim 19, further comprising washcoating an oxidation catalyst washcoat containing a platinum group metal extending from the outlet end of the passage over a length in the range of 10% to 50% of the wall length.

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